1 Final Report on the Safety Assessment of DMDM Hydantoin

Abstract

DMDM Hydantoin is a preservative, which is used in cosmetic products at concentrations up to 1%. This ingredient is a formaldehyde donor containing up to 2% of the free aldehyde in equilibrium with the hydantoin. When 14C-DMDM Hydantoin was applied to the middorsal area of Sprague-Dawley rats, more than 98% of the recovered radioactivity was confined to the dose site. The LD50 dermal and oral toxicity of DMDM Hydantoin was greater than 2 g/kg. No significant toxic effects were noted in a subchronic oral toxicity study. In skin irritation studies using product formulations, results ranged from non-irritating to moderate skin irritation. At most, transient minimal irritation was noted in albino rabbits treated with DMDM Hydantoin formulations. The mutagenicity of DMDM Hydantoin formulations varies in accordance with the test system. The ingredient was not mutagenic in one Salmonella/microsome assays but was in another. Both positive and negative mutagenic activities were reported when DMDM Hydantoin was tested in the L5178y TK± mouse lymphoma assay. The ingredient was mutagenic in the chromosome aberrations and unscheduled DNA synthesis assays but was not mutagenic in unscheduled DNA synthesis and DNA strand breaks/crosslinks assays. A comparison of Ames test results from studies of DMDM Hydantoin product and formaldehyde indicates a similar number of reversants per formaldehyde equivalent. In clinical studies, skin irritation ranged from none to observations of intense erythema and edema when various formulations containing DMDM Hydantoin were applied. DMDM Hydantoin formulations did not induce sensitization in some clinical studies. DMDM Hydantoin formulations were neither phototoxic nor photoallergenic. Use of DMDM Hydantoin at its current concentration of use in cosmetic products would not expose the consumer to levels of formaldehyde above the limit previously considered as acceptable in cosmetic products. Based on the available data included in this report, it is concluded that DMDM Hydantoin is safe as a cosmetic ingredient in the present practices of use.